This will allow you generate a filter list based on live registry data.
(You can also use a regular 'whois' client against filtergen.dan.me.uk to get the same output)

Options:	Enable Debug Mode Generate IPv6 Filter Generate cisco ios-xr juniper force10 mikrotik prefix-list called       Permit up-to prefix size: / (CIDR size, e.g. 24 or 64)
Data Source:	RIPE RADB APNIC
AS-SET to Query:

Output from Filter List Generator:

%
% Filter List Generator
% Copyright(c) 2021, Daniel Austin MBCS
%
% usage:
%   [-D] [-6] [-RIPE | -RADB | -APNIC] [-f filtername -t filtertype [-upto N]] as-set
%
% -D for DEBUG mode (shows working calculations)
% -6 for IPv6 filter generation
% -RIPE for whois.ripe.net lookups
% -RADB for whois.radb.net lookups
% -APNIC for whois.apnic.net lookups
% -f will generate a cisco-style filterlist called 'filtername' (use -t filtertype as follows)
%      cisco (default)
%      iox-xr
%      juniper (basic support)
%      force10
%      mikrotik
% Additionally, if using -f/-t you may specify -upto N where N is the prefix size to permit up-to
%
% Using whois.radb.net for lookups
% Generating filter list for 'AS133579'
101.100.128.0/19
101.100.128.0/24
101.100.129.0/24
101.100.130.0/24
101.100.131.0/24
101.100.132.0/24
101.100.133.0/24
101.100.134.0/24
101.100.135.0/24
101.100.136.0/24
101.100.137.0/24
101.100.138.0/24
101.100.139.0/24
101.100.140.0/24
101.100.141.0/24
101.100.142.0/24
101.100.143.0/24
101.100.144.0/24
101.100.145.0/24
101.100.146.0/24
101.100.147.0/24
101.100.148.0/24
101.100.149.0/24
101.100.150.0/24
101.100.151.0/24
101.100.152.0/24
101.100.153.0/24
101.100.154.0/24
101.100.155.0/24
101.100.156.0/24
101.100.157.0/24
101.100.158.0/24
101.100.159.0/24
103.237.40.0/22
103.237.40.0/24
103.237.41.0/24
103.237.42.0/24
103.237.43.0/24
158.140.224.0/20
158.140.224.0/24
158.140.225.0/24
158.140.226.0/24
158.140.227.0/24
158.140.228.0/24
158.140.229.0/24
158.140.230.0/24
158.140.231.0/24
158.140.232.0/24
158.140.233.0/24
158.140.234.0/24
158.140.235.0/24
158.140.236.0/24
158.140.237.0/24
158.140.238.0/24
158.140.239.0/24
158.140.240.0/21
158.140.240.0/24
158.140.241.0/24
158.140.242.0/24
158.140.243.0/24
158.140.244.0/24
158.140.245.0/24
158.140.246.0/24
165.173.60.0/22
165.173.60.0/24
165.173.61.0/24
165.173.62.0/24
165.173.63.0/24
% end of filter list for 'AS133579' (68 prefixes found) 
% took 0.34 secs for query (0.20 secs of connection time)
% used 1 connections -- 374 lines of whois data parsed